The present invention relates to a camera of changeable focal length, and more particularly to a camera equipped with a taking lens which is changeable as to focal length.
Recent compact cameras are equipped with zoom lens systems. To change the focal length, such a zoom lens system includes a cam cylinder driving a movable lens component of the zoom lens system, thereby changing the focal length thereof.
It is difficult to make the cam cylinder with high precision but low cost. To remedy this; it is possible to provide a taking lens system which is changeable between only two different focal lengths. Although such a taking lens system, which usually comprises a combination of a master and a conversion lens, needs no cam cylinder and so can be provided at lower cost, it is impossible to change the focal length progressively as in zoom lens systems.
Compact cameras having zoom lens systems, in particular motor driven zoom lens systems, are provided with zoom finders of which the focal length is changed upon changing the focal length of the zoom lens system, thereby matching the field of view of the finder system with that of the zoom lens system. Upon taking a picture, it is almost certain that zooming will take place in order to find the most suitable field of view for the zoom lens system. This drives the motor so frequently that the battery is soon run down.